The Fragile Families and Child Wellbeing Study (FFS) is a nationally representative, birth cohort study of approximately 4900 children born in large US cities (populations of 200,000 or more) between 1998 and 2000. The study includes: (1) interviews with mothers and fathers at birth and again when children are 1, 3, 5 and 9 years old, (2) medical records for a subset of mothers and children at birth, (3) in-home assessments of children and their home environments when children are 3, 5, and 9 years old, (4) interviews with children at age 9, (5) interviews with teachers when children are 3, 5, and 9 years old and (6) DNA samples from mothers and children when children are age 9. The study also includes in-depth, longitudinal interviews with a subset of approximately 75 couples during the first four years after the child's birth. The study design called for a large oversample of births to unmarried parents, and thus the data are a valuable resource for studying health disparities among minority and economically disadvantaged populations. To date, more than 1300 researchers have downloaded the public use data, and Google Scholar lists 730 scholarly articles, theses, books, and abstracts using the FFS data for the period covered by the current NICHD grant, 2006-2011. We seek funding to conduct another round of interviews with mothers and children when children are 15 years old. Our specific aims are to: Update information on children's health and development and collect new data on health and health risk behavior, school performance, and anti- and pro-social behavior when children are age 15 Update information on contextual factors, including families, neighborhoods, schools and peers, when children are age 15, including retrospective data on family experiences since the last interview Collect saliva samples from 3,600 children at age 15 to be used for future methylation analysis Approximately 3600 mothers and 3100 children will be interviewed via phone. These phone interviews will be 55 minutes for mothers and 45 minutes for children. Five hundred adolescents will be interviewed in person for approximately 1 hour.